A 330-kv air switch

PREPARATORY WORK and preliminary design on an air switch to meet the 330-kv American Gas and Electric system requirements began several years ago while the general insulation problem of the system was being studied. After the 1,300-kv level, a stack of insulators seven high was selected for the switch; many preliminary tests were made on the stack. Various combinations of insulators were tested for strength and deflection and comprehensive corona and radio noise tests were conducted. Various switch types, vertical break, horizontal break, single break, double break, and multiple break, were studied and the vertical break chosen. However, if voltages are carried to any considerable distance beyond 330 kv, some sort of split-blade switch can be expected to reduce the extremely long blade length.